Bug 2543241 (CVE-2026-102598) - CVE-2026-102598 werkzeug: werkzeug: Denial of Service via safe_join() Windows special device paths
Summary: CVE-2026-102598 werkzeug: werkzeug: Denial of Service via safe_join() Windows...
Keywords:
Status: NEW
Alias: CVE-2026-102598
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
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Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-29 15:35 UTC by OSIDB Bzimport
Modified: 2026-10-05 09:09 UTC (History)
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Description OSIDB Bzimport 2026-09-29 15:35:25 UTC 
Werkzeug is a comprehensive WSGI web application library. Prior to 3.1.9, the safe_join function used by send_from_directory can allow a NUL: special-device path because safe_join checks the Windows device name without first removing an empty NTFS ADS marker. The trigger is that an application runs on Windows with NTFS and serves a user-specified path ending in a special device name such as NUL:. The attack mechanism is that a requested path ends in a Windows special device name with an empty ADS marker. The impact is that the special device opens successfully and the file read hangs indefinitely. This issue is fixed in version 3.1.9.
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